Photographic emulsions containing heterocyclic nitrogenous cyanine dyes having a newgroup attached to the nitrogen atom thereof



Aprll 18, 1950 w s 2,504,616 I PHOTOGRAPHIC EMULSIONS CONTAININGHETEROCYCLIC NITROGENOUS CYANINE DYES HAVING A NEW GROUP ATTACHED TO THENITROGEN ATOM THEREOF Original Filed Sept. 7. 1946 EMULSION CONTAININGDYE OF EXAMPLE I FIG. 1

EMULS/ON CONTAINING DYE OF EXAMPLE I FIG. 2

EMULSION CONTAINING DYE OF EXAMPLE XI ALFRED W. -AN/SH INVENTUR PatentedApr. 18, 1950 PHOTOGRAPHHC EMULSIONS CONTAINING HETERQEYKCLICNITROGENOUS CYANINE DYES HAVING A NEW GROUP ATTACHED TO THE NITROGENATOM THEREOF Alfred W. Anish, Vestal, N. Y., assignor to GeneralAniline& Film Corporation, New York, N. Y., a corporation of Delaware Originalapplication September 7, 1946, Serial No.

695,559, now Patent No. 2,453,738, dated November 16, 1948. Divided andthis application November '7, 1946, Serial No. 708,472

7 Claims.

This invention relates to heterocyclic nitrogenous cyanine dyescontaining a new group attached to the nitrogen atom thereof, andparticularly to photographic light-sensitive silver-halide emulsionscontaining the same.

sensitizing dyes used with silver-halide emulsions must not only providethe desired sensitivity, but must meet other requirements, chief ofwhich are non-difiusibility in the emulsion and solubility in liquidsused for adding the dye to the emulsion. A dye selected for itssensitizing power need not, and usually does not have such otherprerequisites.

It is known that variations of the structure of a sensitizing dye leadto changes in its sensitizing characteristics. Hence, if a dye besatisfactory from the standpoint of its sensitivity, but deficient fromthe standpoint of solubility or diffusibility, and it is attempted tocure the deficiency by the introduction of substituents changing the dyemolecule, a modification of the sensitizing characteristics necessarilyensues.

It is recognized in the art that the greater the molecural weight of aproduct, the lower its solubility; discounting, of course, the presenceof solubilizing groups. Hence, if a sensitizing dye is deficient fromthe standpoint of diffusibilty and satisfactory from the standpoint ofsolubility a change in the size of the molecule to cure the deficiencycauses a lessening of solubility.

It is also a truism that the characteristics of a cyanine dye will notvary greatly if the aliphatic atom grouping attached thereto is variedwithin limits. Thus, it is possible to use interchangeably the lowmolecular weight aliphatic radicals ranging up to say 4 carbon atomswithout a material modification of the properties of the dye. However,if this limit be exceeded to increase the size and hence thenon-diffusibility of the dye as a whole, then again we find that the dyehas undergone a marked departure in properties from those of theoriginal.

I have now discovered that by introducing one or two methylene groupsbetween a p-toluenesulfonate group and a nitrogenous heterocyclicsystem, compounds are obtained which, when utilized as alkylating orquaternizing agents for basic nitrogenous heterocyclic dye intermediatesusually employed in the production of sensitizing dyes, yield dye saltintermediates which undergo the usual reactions for the preparation ofcyanine dyes. These dyes are characterized not only by their speed andgradation but also by non-diiiusing properties in multilayer filmswithout any sacrifice in solubility.

An object of the present invention is to provide a photographic elementcomprising a light-sensitiVe silver-halide emulsion sensitized withheterocyclic nitrogenous cyanine dyes containing a new group attached tothe nitrogen atom thereof.

A further object is to provide sensitizing dyes which are characterizednot only by their speed and gradation, but also by their non-diffusingproperties in multilayer films without any sacrifice in solubility.

Other objects and advantages of this invention will become apparent byreference to the following specification in which its preferred detailsand embodiments are described.

I have found that when an aromatic primary amino compound, containing inaddition a hydroxy, mercapto, or selenyl group in the orthoposition isheated with glycolic or hydracrylic acid, azoles are obtained, whichupon further treatment with p-toluenesulfonyl chloride, yield azoletoluenesulfonic acid esters, which are excellent alkylating orquaternizing agents for basic heterocyclic nitrogenous intermediatesusually employed in cyanine dyes.

The alkylating or quaternizing agents prepared according to the presentinvention are characterized by the following general formulae:

wherein R. represents hydrogen, an aliphatic radical such as an alkylgroup, e. g., methyl, ethyl, propyl, butyl, and the like, alkoxy, e. g.,methoxy, ethoxy, propoxy, etc., halogen, e. g., chlorine or bromine, oranilinegroup, R1 represents either hydrogen, a halogen, or an aliphaticradical of the same value as R, R2 represents either hydrogen or analiphatic group of the same value as R, X represents either oxygen,sulfur or selenium, and n represents a numeral ranging from 1 to 2.

The aromatic primary amino compounds containing a hydroxy, mercapto orselenyl group in the ortho-position and utilized as starting materialsfor the preparation of the above alkylating 3 or quaternizing agents arerepresented by the following general formulae:

laez, is heate d with a slight excess of a molecular HO- (CH2) n-COOH vhi 'inir stre ts Jalfxiu ia ra i rb to 2, at a temperature ranging from12 155 0., for several hours. The methods of isolating the resultingproduct vary with the nature of the ;aromatic primary amino compound andthe orgarlic, acid employed in the condensation reaction In thecasewhere the reaction mixture consists of an 2 -aniinobenzenethiol, orZ-aminobenzeneselenol and glyc olic acid the product is pisolated by,diluting .the reaction mixture with ,water at room temperature, and asufficient q tyq ami d xidiz pe' s nt su a a 3% solution of hydrogenperoxide, aqueous solution of NaQfipotassium ferricyanide, sodiumperoxide sodium perborate, oxygen/etc, is added'until "ii/solidprecipitateensue's. The purpose of the oxidizing agent is to convert theurireacted benzenethiol or benseneselenol selenomercaptan to theinsoluble disuliide or diselenide. The precipitate is separated from theliquid portion of the reaction mixture, redissolved in a minimum amount-'of 3N sodium hydroxide solution, in which the 2-hydroxymethyl azole issoluble, and the -solution treated with a small quantity of charcoal,and the compound reprecipitated care fully by the addition of a 10%solution of acetic uaq a ,Anaddi ionali ap on of. h finalp uct may beobtained from the filtrate by saltingout with sodium chloride. v v VWhere th on m xt r on t o a aminobenz enethiol or aminobenzeneselenol,and hydracrylic acid, the unreacted portion of the aminoben zenethiol oraminobenzeneselenol, is I, extraoted with a ito 10% solution of sodiumhydroxide in which the final product is insoluble,

(the extract rendered slightly acid, and the insoluble portior'i'extracted with a water immiscible solvent such as ethyl ether, petroleumether, 'benzene i'and; the like. The residue remaining aitendistilling01? the ether is then subjectedto a fractional distillation.""The'distillate obtained above 150 C., and 2 mm. pressure is utilized inthereaction with p-toluenesulfonylchloride.

In the {case where ananiinoph'enol and glycolic or hydracrylic acid isused, the reaction mixture extracted several times with ether, theextract driedwith anhydrgus sodium sulfate, and thertether:distilledflpfi. The oily residue remaining after distilling othe ether is subjected to a fractional distillatlon'under reducedpressure. All 'ofthe'dis'tillate' iibtained above 150 C., at 2-3 mm.'of'pressiure is mainly an alkylol-benzoxazole, and: utilized as"''sluch in the reaction with the p'-tol1ie'rie'sulfonyl* chloride. U Qnernoi of the product as above obtained is dissolved iniaj sumcientquantity of 8N sodium i hydroxide solution and the solution heated on a"steam bath. *Tdthe hot solution, 1 mol of ptoluenesulfonyl chloride isadded and the mixture allowed to stand at room temperature for 3 or morehours v The precipitated product is "recovered fby filtration," washedwithwa'ter; the solid dried in air,"and-recrystallized} from'petroleumether, 7

When a momm equivalent of 2'-'amirlobnzenethiol is heated "with a slightexcess-er a molecular equivalent o'i -fglycolic a d'ahdthe resuiting z-hydroxymethylbenz tliiazole reacted withpetoluenesulfonyl chlor'i"twor'eactionsbc- "cur which may be-writtenflas follows:

+HOOOCHzOH "NH: Us

JO o' o'Hi' oH l-oisoi "oi1;

c) s\ A5 l o CHl o 'SW-Q' cm The"toluenesulfonicester (c) so prepared isthen reaiitedtvithany one of the nitrogenous hetelfdcyclic-"bases,-usually" employed in the nth'esi's' of oyaninedyes, in the known manner,such a's byheatin'g ina'sealed tubeiat a temperaftiire rangingrromJto'150" C. Another'meth. 6 0d comprises" heating said-r 'ester and'baseat "about 1 100 Ci; with a isoivent diluent'; for a time""siiifici'ent ior quatern'ization to "take place.

The heterocyclic' nitrogenous "cy'a'iiine dye" in- "terminates"abstaining anew 'g roup attached to nitro'ggsen'- tom {thereof andprepared according to" "the present invention are 'characterized 'bythefollowing general formulae:

i "/Y 55 b- Ra cum 0 t s'oi and are presented merely for the purpose ofillustration and are not to be construed as limitative.

Example I C-CHPO-SOIGCHI 2-benzothiazolylmethy1 p-toluenesulfonate Sixtygrams of Z-aminobenzenethiol and 42 grams of glycolic acid were heatedtogether at '120l55 C., for several hours. The-mixture was poured intowater at room temperature and 10 cc. of a 3% hydrogen peroxide solutionadded. The precipitate is separated from the liquid portion of thereaction mixture, redissolved in a minimum amount of 3N sodium hydroxidesolution and filtered. A small quantity of charcoal was added, theproduct reprecipitated carefully by the addition of a 10% solution ofacetic acid, and the solid product recovered and dried.

Sixty grams of the product as above obtained is dissolved in 500 cc. of8N sodium hydroxide solution and the solution heated on a steam bath. Tothe hot solution '70 grams of p-toluenesulfonyl chloride was added andthe mixture allowed to stand at room temperature for'several hours. Theprecipitated product was cooled, filtered, washed with water, the soliddried in air, and recrystallized from petroleum ether.

Example II s 2-benzothiazolylethyl p-toluenesulfonate Fourteen grams ofZ-aminobenzenethiol and 11 grams of hydracrylic acid were heatedtogether at 140155 C., for two hours. The gummy prod not, which issoluble in acid but insoluble in alkali, was extracted with a solutionof sodium hydroxide so as to remove anyvunreacted Z-aminobenzenethiol.

The insoluble residue was extracted several times with ethyl ether, andthe residue remaining after distilling off the ether was subjected to afractional distillation above 0., and at 2 mm. pressure. The distillateobtained at -170 C., at 3 mm. pressure, was a yellowish-brown oil.

The yellowish-brown oil obtained as above was then reacted withp-toluenesulfonyl chloride as in Example I.

Example m N o-om-o-sol--om .Z-benzoxazolylmethyl p-toluenesulfonateFifty-four grams of Z-aminophenoland 42 grams of glycolic acid wereheated together as in Example I. The reaction mixture was extractedseveral times with ether and then dried with anhydrous sodium sulfate.The residue remaining after distilling off the ether was subjected tofractional distillation under reduced. pressure. The distillate obtainedabove 150 C., and at 2 mm. pressure, was mainlyZ-hydroxymethylbenzoxazole.

The 2-hydroxymethylbenzoxazole as above obtained was then reacted withp-toluenesulfonyl chloride as in Example I.

Example IV Five grams of 2-methylbenzothiazole and 5 grams ofZ-benzothiazolylmethyl p-toluenesulfonate were heated together in a tubein an oil bath for 4 hours at 100 C. The crude solid was, ground with anether-acetone mixture, washedg with acetone, and finally dried.

Example V 0 s HQC/ \G-CH| 7 Three grams of2-methyl-5,fi-methylenedioxybenzothiazole and 5 grams of2-benzothiazolyl methyl p-toluenesulfonate were heated together in atube in an oil bath for 3 hours at 100 C,

sweetie '3 'l he -tcrude fis'olidwa's pulverized Pinan 11 etharsacetonemi xture sandrwashed with acetone.

OH: I

Five grams -11 of 1.4;-diphenylrZemethyIthiazoIe ,and 5 grams of2-benzothiazolylmethy1petoluenedeem :s'ulf'on'ate 'were heated together:.in a tube in: an

*oil bath for 12 hours at"'65 68 'C. The 'crude .brown solid was groundwith an ether-acetone mixture andi'finally i washed with acetone. ZLhefinalproductdecomposes at 100 C. i

- iiExample VII CHI Five grams of 6-methoxy-2-methy1benzoselenazole and5 grams of Zbenzothiazolylethyl p-toluenesulfonate were heated-togetherin a tube in an oil bath f0r12r hours atA- 6568 C. The crude productwasv washed'withan ether-acetone mixture and then acetone in .a mortar.The final product decomposes at 100 C.

Example VIII Five grams each of z-methylbenzothiazole and2-benzoxazolylmethyl p-toluenesulfonate were heated together in atube--in an oil bath for 4-5 s irrespectiverof lthe chain iengthroflthedyestum or grouping in 2-position to the nitrogen atom thereoi ExampleIX I -Five tenthegrams each or 5-acetanilidoniethylfonate preparedaccordingto' Example 'IV-were dissolved 1510-00. 015 isopropylalcoholandrefluxed in' the'presence of 1.0 cc. of triethylamine for'2-hours. "The=dye was filtered off after cool- "ing; and boiled out twicewlth alcohol. Itssen- 'sitizing speed in bromoiodide emulsions is 100%greater than that of =a-corresponding dyehaving -an ethyl"gi'oup'-atta'ched'to the nitrogen atom of the ben-zothiazole" nucleus.

Emample X One gram escno'fiZ- (B-acetalnilidovinyl) 513 me'thylenedioxyben'z'ot'hiazol ethiodideand 2 methyl 5,6 -'""me'th'ylenedi'oxy 3 (2'ben- 'zothiazo'lylmethyl)benzothiazole p tolueriesulfonateprepared"according toExample V were -dissolvedin"20i0 cc. ofrpyri'dineand" 0.5 cc; of

ftriethylam ineladded. 'Th'eimixture was heated 'coVerstearn for 1'hour, then cooled. and'filtered.

"The "residue on the filter was recrystallized twice from methylalcohol.The dye sensitized a silver brornolodide emulsion to about 680m"with'a"maximum' at 640 me.

I EwampZeXI (!J\ S N Five-tenths grams each of Z-(Q-ac'etariilidovinyl)benz'oxa'zole'ethiodidearid 2'-meth'y1-3- (2'- benzothiazolylmethyl)--benzothiazo1e .p-toluenesnlfonate?preparedaccording to Example IV-were heated in c 15.02 cc. of pyridine in the presence 0f 0J5gramrofatriethylamine at7l200 C; for 1'5'min-' utes. The r-eactio'nm-i-Xt'ure was-:cooled,' diluted witn an equalvolume of water,'-and-a1iowed='to 9 stand at room temperature. The dye crystals werefiltered off, boiled out with two portions of methanol and thencrystallized from ethanol. The dye sensitized a silver-bromoiodideemulsion to about 600 m with a maximum at 560 nm, and had a strongersensitization in this type of emulsion than the corresponding dye withethyl groups on both nitrogen atoms.

Example XII (hHt O HIO Example XIII Two and six-tenths grams of2-methyl-4- acetanilido-methylene--thiophenenone- (5) and 4.7 grams of2-methyl-3-(2'-benzothiazolylmethyhbenzothiazole p -toluenesulfonateprepared accord'ng to Example IV were dissolved in 50.0 cc. of isopropylalcohol and 0.5 cc. of triethylamine added. The mixture was refluxed for30 minutes, then cooled and the dye filtered oil. The dye was purifiedby dissolving in dioxane and precipitating with alcohol.

This dye increased the light sensitively of a photographic emulsionconsiderably more than the corresponding dye with an ethyl groupattached to the nitrogen atom.

Three and nine-tenths grams of 2-(fi-methylmercaptovinylbenzothiazoleethiodide and 1.5 grams of 3-ethylrhodanine were condensed by refluxingfor 1 hour in cc. of isopropyl alcohol in the presence of 1.0 cc. oftriethylamine. The dye which settled out on cooling was filtered off andreacted further without purification.

Two and five-tenths grams of the merocyanine thus prepared werealkylated with 3.0 cc. of dimethyl sulfate by heating together at 100C.forl0 minutes. The reaction product was cooler, chilled, and theexcess of dimethyl sulfate decomposed by adding pyridine.

Three and six-tenths grams of 2-methyl-4,5- dipheny1-3-(2-benzothiazolylmethyl) thiazole ptoluenesulfonate prepared accordingto Example VI were added and the mixture heated at C. for 15 minutes.The rhodacarbocyanine dye was isolated by boiling the crude reactionproduct with dioxane to remove impurities and then recrystallized frommethyl alcohol. The dye sensitized color film strongly with a maximum at640 my.

Example XV CH3 o --1-CH=CHCH=C Three grams each ofZ-(fi-acetanilidovinyb- 5,6-dimethy1benzoxazole ethiodide and Z-methyl-3-(2-benzothiazolylmethylbenzothiazole p-toluenesulfonate preparedaccording to Example IV were dissolved in 90.0 cc. of pyridine to which0.5 cc. of triethylamine was added, and the mixture heated on a steambath for 15 minutes. The reaction mixture was cooled and diluted with anequal volume of water and allowed to stand at room temperature. The dyecrystals were filtered oil and recrystallized twice from ethyl alcohol.The dye sensitized a silver-hromoiodide emulsion to 600 m with a maximumat 565 m In color emulsion compositions, this dye had a speed 5l-100%greater than the corresponding dye with an ethyl group attached to thebenzothiazole nucleus.

Example XVI Four and eight-tenths grams or 2-methyl-3-(2-benzothiazolylethyl)benzothiazole p-toluenesulfonate (prepared byheating a molecular equivalent of2-benzothiazolylethyl-p-toluenesulfonate of Example II with a molecularequivalent of 2-methy1 benzothiazole) and 2.0 grams of 3- EmampZe XVII iis. t

Four and. eight-tenths grams of 2-methyl-3- (2 -'benzothiazolylmethyl)benzothiazole p tolu-x enesulionate prepared. according to Example IVand 3.5 grams of "Z-methyimercapto onethyl g quinoline ethiodide weredissolved in 10M) cc. of: methyl alcohol and brought to near 10011...Gradu allyi-LO cc. of triethylamine was addedand the mixture refluxedfor 15 minutes, thencallowedi to cool. The yellow dye crystals whichseparated.

out were filtered off and recrystallized frommethanol'. The dyesensitized a silver-b'romoio'didea emulsion to 560 m with a maximum at536 m Example :XVIIL;

One and one-half grams'of p dimethylaminm benzaldehyde and 4.8grams'of12methyl-5- 2 henzoth azolylmethyl)benzothiazole p-toluenesuifcnateprepared according to Exainple-lv'were dissolved in 30.0 cc. ofpyridineiand the mixture heated at an oil bath temperature measuring 119so The dye Whichiormed precipitated out upon dilution with Water. Thedye crystals were recrystallized from methyl alcohol have absorptionmaximum in alcoholic solution at about 555 m Example XIX EXample'XIIIwas repeated with the exception .2 that an equivalent quantity of2-methyl-3-(2f benzothiazolylmethyl)benzothiasole p-tcluenepreparedaccording to Example VIII, substituted for Z-methyl-E-(2f-benzothiazothyl) bensothiasole p-toluenesulfonate.

This dye increased the light sensitivity of a. photographic emulsionconsiderably more than. the corresponding ,dye with an ethyl groupattached to the nitrogen atom.

While the foregoing dye salts have been prepared inzthe form of thepreferred iodide, it is clearly apparent thatthey can also beprepared inthe form of a bromide, chloride, perchlorate, sulfate,p-toluenesulfonate, and the like by uti-i lizing, as a startingcomponent, the correspond-e ing quaternary ammonium salt of aheterocyclic nitrogenous dyestufi intermediate of the type used inpreparing cyanine dyes. Moreover, the anions of the dye salts as aboveobtained are readily converted into difierent anions by meth--. odswell-known to the art.

In the preparation of photographic gelatinosilver developing outemulsions, such as gelatinosilver-chloride,gelatino-si1ver-chlorobromide, gelatino-silver-bromoiodide emulsions,and'the like, containing the monoand polymethine'dyestuiis of thepresent invention, it isonly neces-- sary to disperse the dyestufisin'the'emulsions. It is convenient to add the compounds from solutionsin appropriate solvents; An alcohol, such as methanol or ethanol, issatisfactory as a solvent for the dyestuffs.

Emulsions prepared in accordance' with this" ,invention can be coated inthe .usual manner upon any desired support, such as cellulose nitrate,cellulose acetate, polyvinyl acetal. resin; glass, paper, and the like.

The concentration of these new dyestuffs in the emulsion can varywidely, i. e., from about 1 to about 100 mg. per liter of flowableemulsion. The concentration of the dyestuif will vary according to thetype of light-sensitive material in the emulsion and according totheeffect desired. The suitable and most economical concentration forany given emulsion will'be apparent to those skilled in the art uponmaking the ordinary tests and observations customarily used in the artof emulsion making.

The cyanine dye intermediates prepared in accordance with the presentinvention are not only useful for the preparation of cyanine dyes, butalso as supersensitizing agents for photographic emulsions. Inactualpractice only a very small amountis added to the emulsion justprior to coating to obtain supersensitizing properties. Thev actualamount-employed varies but on the average 3-10 rugs. are added insolution to 100 cc. of photographic emulsion containing sensitizingdyes.

The diagrammatic spectrograms. constituting the accompanying drawingillustrate-the regions of the spectrum to which theheterocyclicnitrogenous cyanine dyes containing a nuclear group attached to thenitrogen atom thereof will sensitize: ""a silver-bromoioclide emulsioncontaining 4-5% of 5 silver, halide and the extent of the sensitization;at variousltvavelengthsn The three figures of this; drawing illustratethe sensitizing properties of S the dyes prepared accordingtoExamplesIX, X.

and XE.

This application is a division of my co-pendlng application Serial No;695,559, filed September 7, 1946, now United st'ates Patent 2,453,738,dated November 16, 1948.

While there have been pointed out above certain preferred embodiments ofthe invention, the same is not limited to the foregoing examples,illustrations, or to the specific details given therein, but is capableof variations and modifications as to the reactants, proportions andconditions employed. Accordingly, it is intended that the invention bedefined only by the accompanying claims.

I claim:

1. A photographic gelatino silver-halide emulsion containing a cyaninedyestufi in which at least 1 nucleus attached to the methine chain isselected from the class consisting of those of the following generalformulae:

and

and the quaternary ammonium salts thereof, wherein R represents a memberselected from the class consisting of hydrogen, halogen, aliphatic, andanilino groups, R1 represents a member selected from the classconsisting of hydrogen, halogen, and aliphatic groups, R2 represents amember selected from the class consisting of hydrogen and aliphaticgroups, X represents a member selected from the class consisting ofoxygen, sulfur, and selenium, Y represents the atoms necessary tocomplete a heterocyclic nitrogenous nucleus, and n represents a numeralranging from 1 to 2.

2. A photographic gelatino silver-halide emulsion containing a cyaninedyestufi in which at least 1 nucleus attached to the methine chain hasthe following formula:

wherein Y represents the atoms necessary to complete a heterocyclicnitrogenous nucleus.

14 3. A photographic gelatino silver-halide emulsion containing acyanine dyestuff in which at least 1 nucleus attached to the methinechain has the following formula:

wherein Y represents the atoms necessary to complete a heterocyclicnitrogenous nucleus.

4. A photographic gelatino silver-halide emulsion containing a cyaninedyestuff in which at least 1 nucleus attached to the methine chain hasthe following formula:

least 1 nucleus attached to the methine chain has the following formula:

6. A photographic gelatino silver-halide emulsion containing a cyaninedyestuff in which at least 1 nucleus attached to the methine chain hasthe following formula:

7. A photographic gelatino silver-halide emulsion containing a cyaninedyestufi in which at .mtbmwham The-following-referencp eSflare-loi figcprd in the q July 19.42",

ALERED w. ANISI-I. m;

1. A PHOTOGRAPHIC GELATINO SILVER-HALIDE EMULSION CONTAINING A CYANINEDYESTUFF IN WHICH AT LEAST 1 NUCLEUS ATTACHED TO THE METHINE CHAIN ISSELECTED FROM THE CLASS CONSISTING OF THOSE OF THE FOLLOWING GENERALFORMULAE: